1. Field of Invention
This invention applies to the field of systems and for apparatus which are used as monitoring devices attached to the muzzle end of large caliber guns (opposite breech) for use in measuring gun deflection for calibration purposes. Moreover the invention includes the field of low power, omnidirectional, motion sensors capable of detecting low magnitude vibrations. Lastly, the field of the invention encompasses use of electronic light sources which are used to replace radioluminescent sources such as tritium.
2. Background of the Invention
The specific problem solved by this invention is one of replacing the hazardous tritium light source used in the existing Muzzle Reference System (MRS) found on the M1 series of tanks. However, the invention also applies to any type of artillary where muzzle deflection must be measured. The Muzzle Reference System (MRS) is mounted near the end of the gun (opposite the breech) and is used by tank gunners to measure muzzle deflection for calibration of the fire control computer.
The light source is required when the ambient light is inadequate for accurate measurements. The existing light source in the Muzzle Reference System uses a radioluminescent source, tritium, for illumination. The costs associated with the acquisition, handling and disposal of tritium are high. It is estimated that the Army will save approximately $71M over 10 years by replacing tritium with an electronic light source. Such an action would also eliminate a hazard with the high costs of acquiring, handling and disposing of the tritium that has existed for many years.
Various efforts have been made in the past to solve this major problem with electronic light sources. For example a traditional battery operated light source could be used to replace the tritium based Muzzle Reference System (MRS). Typically, a MRS is used only for minutes out of each year and traditional battery operated devices cannot exploit this fact. The capacity of the battery is constrained by the internal dimensions of the existing MRS (1 inch diameter.times.0.68 inch height) and requires replacement twice per year under continuous operation for the specified LED intensity.
Incorporating an ON/OFF switch into any design is unacceptable because of potential damage to any external wiring and the dangers to the crew associated with operating an externally switched MRS in combat. Maintaining electrical contact with the battery terminals is a major problem given the environmental extremes under which the MRS must operate. In addition, the costs and environmental hazards associated with disposing of tens of thousands of batteries every year are very high. Furthermore, since the Light Emitting Diode (LED) is always active in traditional designs, the entire Muzzle Reference System unit, including the housing must be replaced every five (5) years due to the limited life of the LED.
In U.S. Pat. No. 5,523,742 by Thomas E. Simkins and Mark Johnson, issued on Jun. 4, 1996; U.S. Pat. No. 5,610,590, also by Thomas E. Simkins and Mark Johnson, issued Mar. 11, 1997 entitled, MOTION SENSOR, a motion detection device is described comprising a sensor for providing signals in response to patient movements.
These issued patents embody a sensor which includes a conductive rolling sphere in a cylindrical chamber, having an interior portion locating the sphere therein with conductive end plates and conductive inner surfaces such that movement of the element caused by movement of the cylinder will generate intermittent electrical contact between one end plate and the cylinder wall thus generating the ability to generate an alarm or movement signal for further processing.
Accordingly, it is an object of this invention, using as an element the motion sensor concept embodied in U.S. Pat. Nos. 5,523,742 and 5,610,590 to provide a device which senses when a gun is in use and which automatically powers down when not in use during extended periods of inactivity.
Still another object of this invention is to allow the electric power provided by a battery to the device to have an extended life of an estimated twenty (20) years. Such a battery life would exceed the service life of the guns.
Yet, another object of this invention is to eliminate the required replacement of the electronic light source mounted in the device due to its minimum on time, therefore making MRS housing replacement unnecessary.
Finally, another object of this invention is to allow the battery of the device to be permanently hardwired to the electronics, eliminating the contact problems associated with units that use replaceable batteries.
Other objects will appear hereinafter.